Diane F Kremer

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Levels of fructose 2,6-bisphosphate (F2,6BP) and related metabolites were measured in 8- or 9-day-old barley (Hordeum vulgare L.) primary leaves throughout a 24 hour cycle. Young barley leaves contained about 0.4 nanomole F2,6BP per milligram chlorophyll at the end of a 12 hour dark period. F2,6BP levels increased rapidly following a dark-to-light(More)
Carbon assimilation, translocation, and associated biochemical characteristics of the second trifoliolate leaf (numbered acropetally) of chamber-grown soybean, Glycine max (L.) Merr., plants were studied at selected stages of leaf development during the period from 10 to 25 days postemergence. Leaves of uniform age were selected on the basis of leaf(More)
The activity of sucrose-phosphate synthase (SPS) in 9-day-old barley (Hordeum vulgare L.) primary leaves was measured over a 24-hour period. Extractable enzyme activity was constant in the light, decreased 50 to 60% during the first one-half hour of darkness, and then returned to full activity before the start of the normal light period. Decreases of SPS(More)
Starch, sucrose, and fructose 2,6-bisphosphate (F2, 6BP) levels were measured in pea (Pisum sativum L.), maize (Zea mays L.), onion (Allium cepa L.) and soybean (Glycine max L.) leaves throughout a light/dark cycle. Leaf starch accumulated in pea, maize, and soybean but not in onion. Sucrose was a major leaf storage reserve in pea, maize, and onion but was(More)
Soybean seeds are an important source of dietary tocopherols, but like seeds of other dicotyledonous plants, they contain relatively little alpha-tocopherol, the form with the greatest vitamin E activity. To evaluate potential effects of environmental stress during seed maturation on tocopherols, soybeans were raised in greenhouses at nominal average(More)
High irradiance-acclimated soybean leaves had the same CO(2) exchange rates, but lower starch accumulation rates and correspondingly higher translocation rates than unacclimated leaves. Increased translocation rates were associated with increased sucrose phosphate synthetase (EC 2.4.1.14) activity. Foliar sucrose levels and adenosine diphosphate-glucose(More)
Brown rice is a valuable source of lipid-soluble antioxidants including ferulated phytosterols (i.e., gamma-oryzanol), tocopherols, and tocotrienols. To evaluate the impact of temperature on the accumulation of these compounds, seeds from six different rice lines grown to maturity in replicate greenhouses in Gainesville, FL, were analyzed. The lines(More)
The carbohydrate content of barley (Hordeum vulgare L.) leaves was measured over a 24-hour cycle. Nonstructural carbohydrate accumulation was linear after the 1st hour of light, whereas utilization in the dark was fast initially and slowed as stored reserves were depleted. Sucrose was the most abundant storage form of carbohydrate in the primary leaf.(More)
DNA methylation, the conversion of cytosine to 5-methylcytosine, is an important epigenetic modification involved in gene regulation. DNA methylation is essential for normal development whereas abnormal methylation has been implicated in pathological conditions including cancer. To evaluate the extent and variation of genome-wide DNA methylation and its(More)
Soybean plants (Glycine max [L.] Merr. cv Williams), which were symbiotic with Bradyrhizobium japonicum, and which grew well upon reduced nitrogen supplied solely through N(2) fixation processes, often exhibited excess accumulation of starch and sucrose and diminished soluble protein in their source leaves. Nitrate and ammonia, when supplied to the(More)